PARK CITY, UT: On August 3, 2012, stand-up comic Tig Notaro stepped onto the stage of Los Angeles’ Largo and gave an instantly legendary performance. It came at the conclusion of a three-month period in which she was diagnosed with a dangerous bacterial infection, lost her mother unexpectedly, and was diagnosed with breast cancer. The cancer news came about three days before the performance, and it was a breaking point; suddenly the series of tragedies became funny, it was just so over the top. She greeted the audience with a warm, “Good evening. Hello. I have cancer. How are you?” And she proceeded to execute one of the most breathtaking high-wire acts in stand-up comedy history. Suddenly, she was dying — and a star.

Kristina Goolsby and Ashley York’s documentary Tig, which premiered Monday at the Sundance Film Festival, is about what happened after that. The filmmakers spent much of the next year with Notaro, as she dealt with her weird sudden success, attempted to rebuild her act (“There’s no way to follow up that album”), fell in love, and attempted to start a family via a surrogate pregnancy.

It’s all quite personal, and when an audience member asked Notaro if there was ever a moment where the camera’s glare was too much, she quipped, “Um, the whole time?… I originally thought I was through with the tough stuff, so I thought, Sure, why not? Things are great! And then of course life gets going, and things are great and then they’re not, and I didn’t really didn’t consider or prepare myself. And once I got started it was like, If I’m gonna do this, I’m gonna really do it.”

Stylistically, Tig is somewhat problematic; York and especially Goolsby have a background in reality television, and that pedigree is all too apparent in the way the film is shot and edited, leaning heavily on confessional interviews and montages set to emotional music. But there is enough of Notaro to forgive those infractions, both for fans of the comic and comedy nerds in general.

The filmmakers use that Largo set as a touchstone and reference point, circling back to its themes as a kind of organizing principle, and they offer up a particularly valuable picture of how a working comic goes about finding her sea legs again. When she goes back on stage, six months after the set, she struggles; you see her working to get her confidence back, and to figure out where she goes from there.

“After my life fell apart, I was a shell of human,” she recalled Monday. “I didn’t know I was a Canadian still, I didn’t know what I had to say. I mean, there was so much press, comparing me to Richard Pryor, and I was a truth-telling comedian now — and I would say, Am I? I know I still enjoy silliness too. So it took me a while to just push all that out of my head, and just get onstage and figure out how I really feel. And it turns out, I’m ever-changing.”

The filmmakers’ months of access also allow a candid peek at the comic process. There’s a joke that Notaro tries that first night on stage, but it doesn’t quite work; it becomes the film’s stand-in for the new act, as she spends months working that joke, tweaking and fine-tuning it, until she finally figures out the exact wording and timing that makes it click, and gets the laugh.

And Tig is also the kind of documentary where what it isn’t covered is perhaps as noteworthy as what it is. “Being interviewed through this process of people getting a cut of the film,” Notaro explained at Monday’s premiere, “and then, Gosh, you’ve got such an opportunity to make a statement about cancer or being a woman or being gay, and you didn’t really make a statement. And I was like, well, aren’t I by just my actions? I would rather do than say.” Then, after a perfectly timed half-pause, Notaro added, “I mean, I’ll say a few things too, but…”